Abstract

Background

Inflammatory bowel disease is a group of pathologies characterised by chronic inflammation of the intestine and an unclear aetiology. Its main manifestations are Crohn’s disease and ulcerative colitis. Currently, biopsies are the most used diagnostic tests for these diseases and metabolomics could represent a less invasive approach to identify biomarkers of disease presence and progression.

Objectives

The lipid and the polar metabolite profile of plasma samples of patients affected by inflammatory bowel disease have been compared with healthy individuals with the aim to find their metabolomic differences. Also, a selected sub-set of samples was analysed following solid phase extraction to further characterise differences between pathological samples.

Methods

A total of 200 plasma samples were analysed using drift tube ion mobility coupled with time of flight mass spectrometry and liquid chromatography for the lipid metabolite profile analysis, while liquid chromatography coupled with triple quadrupole mass spectrometry was used for the polar metabolite profile analysis.

Results

Variations in the lipid profile between inflammatory bowel disease and healthy individuals were highlighted. Phosphatidylcholines, lyso-phosphatidylcholines and fatty acids were significantly changed among pathological samples suggesting changes in phospholipase A2 and arachidonic acid metabolic pathways. Variations in the levels of cholesteryl esters and glycerophospholipids were also found. Furthermore, a decrease in amino acids levels suggests mucosal damage in inflammatory bowel disease.

Conclusions

Given good statistical results and predictive power of the model produced in our study, metabolomics can be considered as a valid tool to investigate inflammatory bowel disease.

Notes

Acknowledgements

We thank John Fjeldsted and Christine Miller for their support in the Ion Mobility analyses. This study was funded by Agilent Technologies, Regione Autonoma della Sardegna (L.R.7/2007, Grant Number F71J12001180002), and the Medical Research Council UK (Grant Number MR/P011705/1).

Author contributions

PC, LA, JLG, AM and PU conceived the study, directed the project and designed the experiments. AM, MLS, CP and SL, performed the lipid metabolite profile extraction of the plasma samples. AM and CM performed the polar metabolite profile extraction of plasma samples. AM, CH, JW, JD and SL performed metabolomics and lipidomics experiments and data analysis. AM, CH and ZH, contributed on the lipid targeted analysis. AM wrote the first draft of the manuscript, PC, LA, SL, CH, and JLG contributed to the final version. AM, SL, CH, JLG, PC and LA, critically reviewed the data and the manuscript. All authors read and approved the final version of the manuscript.

Compliance with ethical standards

Conflict of interest

The authors declare no conflict of interest.

Ethical approval

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee (Comitato Etico Indipendente della A.O.U. di Cagliari via Ospedale, 54 - 09124 – Cagliari reference number: PG/2014/11480) and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.

Informed consent

Informed consent was obtained from all individual participants included in the study.